The sliding door for a motor vehicle is typically configured to selectively open an entrance defined between a B pillar and a C pillar of the vehicle body (see JP2006-188089A, for example). The sliding door is provided with an outer panel defining the outer side surface of the vehicle, and an inner panel provided on the inboard side of the outer panel and joined to the outer panel along an outer periphery thereof while a central part of the inner panel is spaced away from the outer panel to define a space between the two panels. Thus, the sliding door has a certain thickness in the transverse direction of the vehicle.
The vehicle sliding door provides an advantage of requiring a relatively small space on the side of the vehicle to allow a passenger to get into and out of the vehicle, but the projecting length of the sliding door when the sliding door is opened is so small that it may present some difficulty for a person approaching the vehicle from the rear to recognize the open state of the sliding door. To alleviate this problem, it has been proposed and/or practiced to attach a lamp or a reflecting plate on a read end of the sliding door. However, the rear end of the sliding door is typically slanted in a forward direction. Therefore, when a lamp is attached to the rear end of the sliding door, the light radiated from the lamp is directed in an oblique direction so that the person approaching the vehicle from the rear may fail to recognize the open state of the sliding door. The same is true with a reflecting plate.